CSF shunts are well known and used broadly to treat patients with chronic hydrocephalus. In simple terms, such shunts typically have an inlet located in the patient's brain, and an outlet into some portion of the body which can accept and expel the excess fluid. A detailed discussion of prior art CSF shunts can be found in Drake et al, The Shunt Book, © 1995 Blackwell Science, Inc. Massachusetts, (“Drake”) the contents of which are incorporated herein by reference.
More particularly, ventriculoperitoneal (“VP”) shunts are designed to drain CSF from the brain into the peritoneal cavity. VP shunts are used in a variety of medical conditions and are implanted in both young and old patients. Certain configurations of prior art VP shunts can include a ventricular catheter, a flow-valve that can be changed by an external magnet, and a tunneled abdominal catheter. Further discussion on this type of shunt can be found in Reinprecht A., et al., “The Medos Hakim programmable valve in the treatment of pediatric hydrocephalus.”, Childs Nerv Syst, 1997 November-December; 13(11-12):588-93. The ventricular cather and flow-valve are inserted through a scalp incision. The major complications from these and other prior art shunts include infection, obstruction, disconnection, under draining, and over draining, all of which can lead to serious injury and even death. The symptoms of shunt failure and malfunction are nonspecific and include fever, nausea, vomiting, irritability and malaise. A patient presenting to a medical facility with such symptoms warrants a thorough radiological, laboratory, and occasionally a surgical evaluation. As known to those of skill in the art, insertion of CSF shunts requires a highly skilled surgeon or radiologist working under CT X-Ray guidance, but once inserted, such shunts are frequently prone to failure.
More recent shunts that attempt to overcome some disadvantages of older shunts include the use of telemetry, as discussed in Miyake H. et al., “A new ventriculpertoneal shunt with a telemetric intracranial pressure sensor: clinical experience in 94 patients with hydrocephalus”, Neurosurgery, 1997 May; 40(5): 931-5 and Munshi H., “Intraventricular pressure dynamics in patients with ventriculopleural shunts: a telemetric study”, Pedatr Neursurg, 1998 February; 28(2): 67-9 Despite the fact that Miyake and Munshi teach the use of telemetrics with shunts, the shunts taught therein are still prone to failure due to infection, blockages and other difficulties, such that failures of such shunts can still require complete replacement of the shunt.